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CVE-2025-39981

Status: DeferredHigh (7.8)—

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: MGMT: Fix possible UAFs

This attemps to fix possible UAFs caused by struct mgmt_pending being freed while still being processed like in the following trace, in order to fix mgmt_pending_valid is introduce and use to check if the mgmt_pending hasn't been removed from the pending list, on the complete callbacks it is used to check and in addtion remove the cmd from the list while holding mgmt_pending_lock to avoid TOCTOU problems since if the cmd is left on the list it can still be accessed and freed.

Technical details traces, logs and code from the original report
BUG: KASAN: slab-use-after-free in mgmt_add_adv_patterns_monitor_sync+0x35/0x50 net/bluetooth/mgmt.c:5223
Read of size 8 at addr ffff8880709d4dc0 by task kworker/u11:0/55

CPU: 0 UID: 0 PID: 55 Comm: kworker/u11:0 Not tainted 6.16.4 #2 PREEMPT(full)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
Workqueue: hci0 hci_cmd_sync_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 mgmt_add_adv_patterns_monitor_sync+0x35/0x50 net/bluetooth/mgmt.c:5223
 hci_cmd_sync_work+0x210/0x3a0 net/bluetooth/hci_sync.c:332
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 home/kwqcheii/source/fuzzing/kernel/kasan/linux-6.16.4/arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 12210:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4364
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 mgmt_pending_new+0x65/0x1e0 net/bluetooth/mgmt_util.c:269
 mgmt_pending_add+0x35/0x140 net/bluetooth/mgmt_util.c:296
 __add_adv_patterns_monitor+0x130/0x200 net/bluetooth/mgmt.c:5247
 add_adv_patterns_monitor+0x214/0x360 net/bluetooth/mgmt.c:5364
 hci_mgmt_cmd+0x9c9/0xef0 net/bluetooth/hci_sock.c:1719
 hci_sock_sendmsg+0x6ca/0xef0 net/bluetooth/hci_sock.c:1839
 sock_sendmsg_nosec net/socket.c:714 [inline]
 __sock_sendmsg+0x219/0x270 net/socket.c:729
 sock_write_iter+0x258/0x330 net/socket.c:1133
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x5c9/0xb30 fs/read_write.c:686
 ksys_write+0x145/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 12221:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2381 [inline]
 slab_free mm/slub.c:4648 [inline]
 kfree+0x18e/0x440 mm/slub.c:4847
 mgmt_pending_free net/bluetooth/mgmt_util.c:311 [inline]
 mgmt_pending_foreach+0x30d/0x380 net/bluetooth/mgmt_util.c:257
 __mgmt_power_off+0x169/0x350 net/bluetooth/mgmt.c:9444
 hci_dev_close_sync+0x754/0x1330 net/bluetooth/hci_sync.c:5290
 hci_dev_do_close net/bluetooth/hci_core.c:501 [inline]
 hci_dev_close+0x108/0x200 net/bluetooth/hci_core.c:526
 sock_do_ioctl+0xd9/0x300 net/socket.c:1192
 sock_ioctl+0x576/0x790 net/socket.c:1313
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf
---truncated---

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

UAF en kernel Bluetooth (AV:L, PR:L) permite lectura de memoria: KASAN detecta acceso a zona liberada; escalada local implícita.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Threat Intelligence ProgramExecution PreventionApplication Isolation and SandboxingExploit ProtectionUpdate SoftwareData Loss Prevention

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Linux — Linux KernelAI

References

Raw JSON (NVD)

Show
{
  "id": "CVE-2025-39981",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "cf75ad8b41d2aa06f98f365d42a3ae8b059daddd",
              "lessThan": "0b60eb04b8524e1b4b3f07fea0d16fda9a677d9a",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "cf75ad8b41d2aa06f98f365d42a3ae8b059daddd",
              "lessThan": "d71b98f253b079cbadc83266383f26fe7e9e103b",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "cf75ad8b41d2aa06f98f365d42a3ae8b059daddd",
              "lessThan": "87a1f16f07c6c43771754075e08f45b41d237421",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "cf75ad8b41d2aa06f98f365d42a3ae8b059daddd",
              "lessThan": "302a1f674c00dd5581ab8e493ef44767c5101aab",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "net/bluetooth/mgmt.c",
            "net/bluetooth/mgmt_util.c",
            "net/bluetooth/mgmt_util.h"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.17"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "5.17",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.6.140",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.59",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.16.10",
              "versionType": "semver",
              "lessThanOrEqual": "6.16.*"
            },
            {
              "status": "unaffected",
              "version": "6.17",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "net/bluetooth/mgmt.c",
            "net/bluetooth/mgmt_util.c",
            "net/bluetooth/mgmt_util.h"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2025-10-15T08:15:36.017",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/0b60eb04b8524e1b4b3f07fea0d16fda9a677d9a",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/302a1f674c00dd5581ab8e493ef44767c5101aab",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/87a1f16f07c6c43771754075e08f45b41d237421",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d71b98f253b079cbadc83266383f26fe7e9e103b",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Deferred",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: MGMT: Fix possible UAFs\n\nThis attemps to fix possible UAFs caused by struct mgmt_pending being\nfreed while still being processed like in the following trace, in order\nto fix mgmt_pending_valid is introduce and use to check if the\nmgmt_pending hasn't been removed from the pending list, on the complete\ncallbacks it is used to check and in addtion remove the cmd from the list\nwhile holding mgmt_pending_lock to avoid TOCTOU problems since if the cmd\nis left on the list it can still be accessed and freed.\n\nBUG: KASAN: slab-use-after-free in mgmt_add_adv_patterns_monitor_sync+0x35/0x50 net/bluetooth/mgmt.c:5223\nRead of size 8 at addr ffff8880709d4dc0 by task kworker/u11:0/55\n\nCPU: 0 UID: 0 PID: 55 Comm: kworker/u11:0 Not tainted 6.16.4 #2 PREEMPT(full)\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014\nWorkqueue: hci0 hci_cmd_sync_work\nCall Trace:\n <TASK>\n dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120\n print_address_description mm/kasan/report.c:378 [inline]\n print_report+0xca/0x240 mm/kasan/report.c:482\n kasan_report+0x118/0x150 mm/kasan/report.c:595\n mgmt_add_adv_patterns_monitor_sync+0x35/0x50 net/bluetooth/mgmt.c:5223\n hci_cmd_sync_work+0x210/0x3a0 net/bluetooth/hci_sync.c:332\n process_one_work kernel/workqueue.c:3238 [inline]\n process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321\n worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402\n kthread+0x711/0x8a0 kernel/kthread.c:464\n ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148\n ret_from_fork_asm+0x1a/0x30 home/kwqcheii/source/fuzzing/kernel/kasan/linux-6.16.4/arch/x86/entry/entry_64.S:245\n </TASK>\n\nAllocated by task 12210:\n kasan_save_stack mm/kasan/common.c:47 [inline]\n kasan_save_track+0x3e/0x80 mm/kasan/common.c:68\n poison_kmalloc_redzone mm/kasan/common.c:377 [inline]\n __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394\n kasan_kmalloc include/linux/kasan.h:260 [inline]\n __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4364\n kmalloc_noprof include/linux/slab.h:905 [inline]\n kzalloc_noprof include/linux/slab.h:1039 [inline]\n mgmt_pending_new+0x65/0x1e0 net/bluetooth/mgmt_util.c:269\n mgmt_pending_add+0x35/0x140 net/bluetooth/mgmt_util.c:296\n __add_adv_patterns_monitor+0x130/0x200 net/bluetooth/mgmt.c:5247\n add_adv_patterns_monitor+0x214/0x360 net/bluetooth/mgmt.c:5364\n hci_mgmt_cmd+0x9c9/0xef0 net/bluetooth/hci_sock.c:1719\n hci_sock_sendmsg+0x6ca/0xef0 net/bluetooth/hci_sock.c:1839\n sock_sendmsg_nosec net/socket.c:714 [inline]\n __sock_sendmsg+0x219/0x270 net/socket.c:729\n sock_write_iter+0x258/0x330 net/socket.c:1133\n new_sync_write fs/read_write.c:593 [inline]\n vfs_write+0x5c9/0xb30 fs/read_write.c:686\n ksys_write+0x145/0x250 fs/read_write.c:738\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nFreed by task 12221:\n kasan_save_stack mm/kasan/common.c:47 [inline]\n kasan_save_track+0x3e/0x80 mm/kasan/common.c:68\n kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576\n poison_slab_object mm/kasan/common.c:247 [inline]\n __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264\n kasan_slab_free include/linux/kasan.h:233 [inline]\n slab_free_hook mm/slub.c:2381 [inline]\n slab_free mm/slub.c:4648 [inline]\n kfree+0x18e/0x440 mm/slub.c:4847\n mgmt_pending_free net/bluetooth/mgmt_util.c:311 [inline]\n mgmt_pending_foreach+0x30d/0x380 net/bluetooth/mgmt_util.c:257\n __mgmt_power_off+0x169/0x350 net/bluetooth/mgmt.c:9444\n hci_dev_close_sync+0x754/0x1330 net/bluetooth/hci_sync.c:5290\n hci_dev_do_close net/bluetooth/hci_core.c:501 [inline]\n hci_dev_close+0x108/0x200 net/bluetooth/hci_core.c:526\n sock_do_ioctl+0xd9/0x300 net/socket.c:1192\n sock_ioctl+0x576/0x790 net/socket.c:1313\n vfs_ioctl fs/ioctl.c:51 [inline]\n __do_sys_ioctl fs/ioctl.c:907 [inline]\n __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0xf\n---truncated---"
    }
  ],
  "lastModified": "2026-07-30T06:24:04.077",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}